Automatic lapping machine



NOV. 14, 1933, H. 1 W|L| s Re. 19,003

AUTOMATIC LAPPING MACHINE Original Filed Dec. 26, 1928 INVENTOR Hbrbev I. Wills ATTORNEY l material and against VLVin a manner to give the arti MSl Reissued Nov.

' 19,003 AUTOMATIC LAPPING MACHINE My invention relates automatic lapping mach be polished are to be which rolls them ar amount of lapping discharge vention is simple character and its action by reason of adjustable stationa tain rotatable Lapping m lapping plate and a llo on paralleler coincide the upper and lower holder which is usua parts'to be lapped in comp ating) path possible non-repe grinding becoming even working on the article.

ers 'have in general shaped matrices which have with the articles tobe gro which, 'due Ito the abrasion, wear rapidly requir- Frequently parts to be matrices with resultant flat is pro-A s'the approach of the lapping ther too closely'and so limits In many cases to grind the'article exg'rinding machines for e'xdies such as piston ing frequent renewals. lapped stick in these In some cases spots.

vided which prevent plates toward each the grinding 'done on the however itis unnecess 'terisivelyV Centerless ample turn out cylindrical bo d into a hopper.

(or iloa H erbert J. Wills, Niagara Falls, N. Y., assigner n to The Carborundum Company Original No. 1,784,648,

' Serial No. 328,556,

cation for reissue November 27,

' 7 Claims.

droppe ound in contact with cle the or abrasive ac nt vertical axes. plates is mounted to be provi stop mechanism articles.

ary

to an improvement in ines, inV which articles tc d into themachine abrasive moving or stationary parts suitable tion before it is 'The object of my into provide a machine which is of a very which is also automatic in the angular relation of an part with respect to certing and stationary parts.) achines ordinarily have an upper wer lapping plate mounted Between a workl ly mounted to carry the licated (and where s to prevent the localized with a resulting un- 'Ihese work-holdded with carefully to be filled by hand und or lapped, and

pins which are uniformv within a few ten thousandths'of an inch. 'Such cylindrical articles lapping'. It is the object of often require therefore o nly a small amount of my invention to lap such articles 1n large numbers, the articles being fed automatically` `the lapping plates ping operation) My invention is illustra ing drawing in which:

vertical Figure 1 is a mediate the operating plates;I

Figure 2 represents a -plan view (seen from at the outer circumferences of and discharged (after the lapthrough an interior opening in thelower lapping plate. j 1 v ted by the accompanysection showing upper and lower operating plates 'and lappingbars interabove), the right half of the upper operating plate having been r emoved;

Figure 3 represents a plan view of the bar;

lapping dated December 9, 1930,

December 26, 1928. .Appli- 1931. Serial Figure 4 is an elevation for the lapping bar;

Figure 5 is a section on and Figure 6 is an edge showing the support the line 5-5 of Fig. 3',

View of the lapping surfaceY 36 showing grooves along which abrasive material distributes itself.

In Figure l a frame 2 carries a lower operating plate 3 which is supported on bearings 4 located about midway between the inner operating plate.

edges of the lower lapping plate is rotated by shaft 'from which the and outer radial The lower means of a driving drive is through a bevel driving gear 6, a driven bevel gear '7, a shaft 8,

a spur pinionl 9 and a spur driven geary 10, which driven gear is secured tothe lower side of the table 3. An upper plate 12 trically with of an extended shaft 1 from a cylindrical portion: meansl of lradial bearings 1 is mounted concenthe lower plate 3 onA the upper end 3. This shaft is separated 14 of the frame 2 by 5. The weight of the upper lplate is carried partly by the parts to be lapped and partly ported'on a step bearing 16.

the shaft 1371s threaded to eng evelled teeth which are engaged by a on 19 mounted on a shaft 20. .The lower e shaft 13 is slidably engaged with the mechanism just described having b bevel pini end of th frame at 2l. With the by the shaft 13` which is sup- The lower end of age with'a nut l'7` the plate 12 may lberaised or lowered by turning4 the shaft 20. l

VA kseries of lapping bars mounted on the frame 2 4in between the lower an Thesebars 30 may be fixed d upper op'er 30 are adjustably `a position to project ating plates. at any desired position to which they have been rotated by tighten- Ing the bolt 31 by mea the head 32. The lapp bar 30 is indicated at 3 ns of a wrench applied to ing surface of the lapping 6. This surface asshown in Fig. 5 has a vertical section which is the arc of a circle. Most of the lapping is done on this circular surface.v In Figure 5 a cylindrical article (to'b'e lapped) 35 is indicated as in contact with a lapping bar 30.

' Abrasive grains carried by suitable vehicles (lubricants, etc!) are'supplied through a cup 33 from which they are fed through a channel 34 and an opening 40 in the working surface ofthe lapping bar.

An index may be provided on the edge 39 of the bar support to indicate various angular positions of the lapping bar 30 with respect to a plane passing through the axis of rotation of the operating plates and the axi lapping har 30.

s of rotation of the The upper operating plate is strengthened by means of radial ribs 37.

In operating the device which is the subject of my invention piston pins or other cylindrical articles are fed by gravity from a hopper to the outer edge of the lower lapping plate. They are' vshown in Fig. 2,'the frictional forces exerted rby the lower plate will tend to carry the articles inward along the lapping bar until they fall through the interior opening 38, into a receptacle beneath. By adjusting the lapping bars to different angular positions as mentionedv above the length of time that the articles are lapped 'may be varied to suit'the amount of lapping required.

While in .the description cylindrical articles such as piston pins have been mentioned particularly as adapted to be lapped by my machine, articles having flat surfaces (either round or rectangular) may also be lapped, in which case, same direction but both .plates are driven in the at different; speeds. v

. By feeding abrasive grains to the outer ends only of the lapping bar, parts may be both lapped Y and polished in one complete operation. The lapping bar may be of cast iron, brass, copper or metal provided with a Wooden face to suit many conditions. f

By applying a brake on the upper plate the y abrasive action may be' considerably increased;

The abrasive action may also be vcontrolled by such factors as the angle of the lapping bar, the speed of the operating plate, the Weight of the top floating plate, the selection of the abrasive, the point of application of the abrasive on the bar, and by the composition of the face ofthe lapping bar.V `A conventional brake 41 risfindicated in Fig. 2. Y v f Both plates and the lapping Abar may be made of an abrasive embedded in vitried clayor rubber. Redmanol or shellac bonds or composite wheels made of iron metal parts and abrasive parts may be used. In this case a thin lubricant would be fed through parts in the lapping bar.

As compared with the priorv art my operating plates do not require frequent resurfacing.A

My machines are particularly adapted for mass production since each Ymachine automatically` laps a large number of articles in succession and one operator-may attend to a number of machines. Y My machine illustrates a novel process of lapping or `grinding cylindrical or spherical parts, particularly in the character of the automatic operation. Theduration of thev automatic lapping process is regulated by-means of anangular difference between the generating. lines of a xed lapping surface and the adjacent .radius` of a roating driving member. Other machines than the one I have illustrated in the drawing may be used for carrying out my novel process, of automatic lapping provided that the driving means simultaneously rotates and translates thecylirk drical and spherical part to'be lapped and provided that the duration of the lappingr pIOess may be automatically regulated by the simpl@ variation of the relative angular position of a rotatable driving means and a stationary lapping means. 1

l. An A `automatic lapping machine for approximately cylindrical parts comprising in combination a lower operating plate ,with plane upper surface and having a central outlet opening, an upper floating plate with plane lower surface, a. lapping bar held in a predetermined position between said lower and upper plates, said lapping bar having -a grooved grinding surface whose generating lines are parallel to said plane surfaces of said plates and are inclined to the adjacent radii of said plates, means for rotating said lower plateto revolve approximately cylindrical objects to be lapped against the grinding vsurface of said lapping bar as well as against the upper plate, the rotation of the lower plate being in such a direction that the frictional forces exerted by the lower plate on the objects to be lapped have components toward the central openf ing of the lower plate, means for adjusting the height of said upper plate above'said lower plate, and means for adjusting the Aangular position of said lapping bar in a plane parallel to the plane Vsurfaces of the plates which contact with the cylinders, whereby ,the time of travel of the cylindrical parts from the circumference of the lower plate tol the central opening v thereof may be varied. s

L2. An automaticlapping machine comprising in combination an operating plate having a plane upper surface and having a central outlet opening, a lapping bar held in a predetermined posi` tion above said operating plate, said lapping bar having a grooved'grinding surface whose generating lines are parallel to the upper surface of said operating plate, and means for rotating said op erating plate to revolve approximately cylindrical objects to `be lapped against the grinding suriii face of saidlapping bar, the rotation of the,

operating plate being in such' a direction that the frictional .forces exerted by the operating plate on the objects to 'be lapped have com--v ponents vtoward the central opening of the operating plate, and'means for adjusting the'an gular .position of said lapping bar in a plane parallel to the upper surface of the operating plate whereby the duration of the lapping of theA articles `tobelapped may be varied at the will' of the operator.

3. The lapping machine described in claim 1.

infwhich the lapping bar contains means for feeding abrasive grains and necessary lubricant at the' lapping Asurface of the lapping bar. y

4, The lapping machine described in claim 2 in' which the lapping bar contains means for feeding abrasive grains and 'necessary lubricant at the lapping surface of the lapping bar.

5. The lappingmachine described in claim 1 s in which the intensity of the lapping action is varied by the application of a brake to the upper plate. s

- 6. An abrading machine for grinding short cylindrical parts or spheres of like diameter comprising a driving member in the form of an annular disk mounted to lrotate around a vertical axis, a stationary but adjustable bar of abrasive material mounted just above said driving member, said bar being recessed along a length which permits simultaneous contact `of the bar with a plurality of parts, anda third member arranged t0 @Online the parts to be abraded while they are mits simultaneous contact of the bar with a plurality of parts, a third member arranged to conne the parts to be lapped While they are rotated against and moved in one direction along the groove of the adjustable bar, and means for supplying nely divided abrasive to the groove.

' HERBERT J. WILLS.

said bar being recessed along a length which per- I 

